Q.E.D. is an acronym or initialism of the Latin phrase quod erat demonstrandum, which means "what was to be demonstrated". In other words, Q.E.D. means "something was to be proven, and now it has been done".
In the European Renaissance, scholars often wrote in Latin. The phrases Q.E.D. was often used at the end of mathematical or philosophical proofs.
Q.E.D. is used in many languages, including:
| Language | Abbreviations | Stands for... |
|---|---|---|
| Arabic | و.هـ.م | وهو المطلوب إثباته |
| Bengali | অ. সি. | অতঃ সিদ্ধ |
| Chinese | 证毕。 | 证明完毕 |
| Croatian | Š.T.D. | što je trebalo dokazati |
| Czech | C.B.D. | což bylo dokázati |
| Dutch | w.t.b.w. | wat te bewijzen was |
| English | w.w.t.b.p. | which was to be proven |
| Esperanto | K.E.P | kio estis pruvenda |
| Estonian | M.O.T.T. | mida oligi tarvis tõestada |
| Finnish | M.O.T. | mikä on todistettu |
| French | C.Q.F.D. | ce qu'il fallait démontrer |
| German | w.z.b.w. | was zu beweisen war |
| Greek | Ο.Ε.Δ. | όπερ έδει δείξαι |
| Italian | C.V.D. | come volevasi dimostrare |
| Hebrew | .מ.ש.ל | מה שצריך להוכיח |
| Hindi | इ.सि. | इति सिद्धम् |
| Polish | c.b.d.u. | co było do udowodnienia |
| Portuguese | C.Q.D. | como queríamos demonstrar |
| Russian | ч.т.д. | что и требовалось доказать |
| Serbian | ш.т.д. | што је и требало доказати |
| Slovenian | q.e.d | (quonc)/konc enga dokaza |
| Tamil | நி.வே. | நிரூபிக்கப்படவேண்டியது |
| Thai | ซ.ต.พ. | ซึ่งต้องพิสูจน์ |
| Hungarian | E.K.B. | Ezt kellett bizonyítani |
| Spanish | Q.E.D. | queda entonces demostrado queda esto demostrado |
| Swedish | V.S.B. V.S.V |
vilket skulle bevisas vilket skulle visas |
| Vietnamese | đpcm. | Điều phải chứng minh |